2020 Research Seminars
In order to reduce the CO2 emissions and comply with international agreements, a strong increase in the use of renewable energy and in the carbon capture technologies is foreseen. Renewables are however intrinsically fluctuating sources, and this leads to periods of power overproduction which needs to be effectively stored. A valid solution is provided by the Power to Gas (PtG) technology. This process uses the excess power to split water and produce H2 (and valuable O2), which is then reacted with CO2 to form CH4 and H2O through the Sabatier reaction. Ni-based catalysts are used for COx methanation, but from a process intensification standpoint highly active Ru is of interest.
In this presentation the reactivity of Ru/Al2O3 catalysts in the PtG process will be investigated. The effect of the metal loading, of the active phase distribution and of the size of the catalytic support is considered, revealing insights on the optimal Ru loading and on the onset of transport limitations, which is relevant for process intensification where almost complete CO2 conversion is needed in compact reactors. The goal is to develop a once-through process producing a gas stream able to meet, without further purifications other than water removal, the stringent purity thresholds required for the direct injection in the gas grid. The reactivity of Ru-based catalysts in the combined CO2 capture and methanation process is also analyzed.
The idea is to capture CO2 from a CO2-containing stream (e.g. combustion flue gases) with a catalytic material (Dual functioning Material, DFM) that acts as a solid adsorbent, and then exposing the CO2-saturated material to a renewable H2-containing stream in order to produce CH4 and regenerate the adsorbent. In this context, mechanistic aspects involved in the CO2 storage and reduction to methane are analyzed by using a model Ru- Me (Me: K, Na, Ba, Ca, Mg) bifunctional catalysts. The interplay between the adsorbent material and the Ru active phase is investigated, and mechanistic implications are discussed.
The direct electron transfer at electrode surfaces is one of the prototypical green technologies of the future and the use of microreactors further advances and simplifies that technology.
The development of a robust and flexible flow microreactor for electrochemistry will be discussed alongside applications in synthesis. Combination with subsequent reactions and inline reaction monitoring allow a rapid integration into synthesis. First examples of stereoselective iodine(III)-mediated reactions will be discussed.
Precisely defined protein aggregates as exemplified by crystals have applications in functional materials. Consequently, engineered protein assembly is a rapidly growing field.
Anionic calix[n]arenes are useful scaffolds that can mould to cationic protein surfaces and induce oligomerisation / assembly. Here, we describe the fabrication of different types of protein frameworks via co-crystallization with sulfonato-calixarene. Calixarene-masked proteins act as nodes within the frameworks, displaying octahedral-type coordination in one case. Such supramolecular protein chemistry may benefit the development of biomaterials and therapeutics.
This seminar will focus on the techniques of continuous processing and mechanochemistry/ball-milling in the context of organic chemistry and, through collaboration, their application to metal-free catalysis, synthesis of pharmaceuticals, agrochemicals and macrocyclic fragrances.
Ammonia (NH3) is a very important molecule with conflicting roles. On the one hand, NH3 is a commodity chemical; its manufacture is integral to the production of fertilizers and polyamides. The oxidation of NH3 on Platinum to NOx (x = 1, 2) is one of the oldest commercialized catalytic reactions; it is the basis for the Ostwald Process for the manufacture of nitric acid. On the other hand, NH3 has emerged as an important reagent in emission control. For the first generation of catalytic converters, NH3 was an inconvenient byproduct and converter design changes were made to minimize its production. For the modern diesel vehicle, NH3 is the NOx reductant of choice. However, due to NH3 toxicity, the NOx reduction must be accomplished without releasing NH3 to the environment by Pt-catalyzed NH3 oxidation. While the Ostwald process relies on high NOx yield, the diesel emission control application requires a high N2 yield.
In this talk we will describe our research in the understanding and design of the structured ammonia slip catalyst (ASC), wherein an NH3 oxidation function is combined with a selective catalytic reduction (SCR) function. We show that a combination of targeted experiments and modeling enable convergence to an optimal architecture that minimizes the Pt loading We will also describe advances in the understanding and modeling of NH3 oxidation kinetics, linking the environmental and chemical manufacturing applications. Finally, we will present a novel core-shell catalyst that comprises a Pt/Al2O3 core and a SCR shell provide for unparalleled ammonia oxidation activity and N2 selectivity.
Dr. Michael P. Harold is the ChBE Chair Professor and Department Chair of Chemical and Biomolecular Engineering at the University of Houston. With expertise in reaction engineering and catalysis, Harold is the author of more than 175 peer-reviewed papers and book chapters and has given over 350 presentations and invited lectures. He is the founder and principal investigator of the University of Houston’s Texas Center for Clean Engines, Emissions & Fuels (TxCEF), established in 2003. Mike was appointed Editor-in-Chief of the AIChE Journal in 2012, the 7th in the Journal’s 60-year history.
A Pittsburgh, Pennsylvania native, Harold received his Bachelor’s degree at Pennsylvania State University, and his PhD from the University of Houston. He joined the faculty at University of Massachusetts at Amherst in 1985 where he became Associate Professor. In 1993 Harold joined DuPont Company, where he held several technical and managerial positions. In 2000 Harold returned to the University of Houston where he became the Dow Chair Professor and Department Chair, a position he held for 8 years. He was re-appointed to that position in early 2013. His honors include the Excellence in Applied Catalysis from the Southwest Catalysis Society in 2019, the Ester Farfel Award at the University of Houston in 2013 (highest honor bestowed on a faculty member) and the American Chemical Society’s Fuel Division Richard A. Glenn Award in 2008.
Professor Harold's research summary can be viewed here: http://www.chee.uh.edu/faculty/harold
Bioactive natural products (also known as secondary metabolites) have an integral role in biology and ecology as well as modern drug discovery and medicine. The McKinnie lab is interested in understanding how natural products are biosynthesized by identifying and characterizing key enzymes involved in their construction.
One particular enzyme family of interest is the vanadium-dependent haloperoxidases (VHPO); these enzymes catalyze the two-electron oxidation of aqueous halide ions to facilitate regio- and enantiospecific halogenation of organic substrates. Currently characterized actinobacterial VHPO homologs are involved in assembling the chemical scaffolds of a variety of meroterpenoid antibiotics with significant activities against multi-drug resistant bacterial pathogens. This seminar will highlight the chemical history of VHPO enzymes, give insight into the versatile range of chemical reactions catalyzed and variable distribution across biology, and suggest future directions towards their adaptation and evolution for chemoenzymatic syntheses.
This talk will take a behind-the-scenes look at Nature Chemistry’s editorial processes, as well as providing some guidance on how to write a paper, how to write an abstract and some DOs and DON'Ts when it comes to titles and graphical abstracts – there will also be some advice on how best to appeal an editorial decision. In addition, there will be a broader consideration of peer review in general, the wider chemistry publishing landscape and also other aspects related to scientific publishing including metrics (impact factor, altmetrics, and so on) and the use of social media.
Stuart Cantrill is a graduate of the University of Birmingham in the UK, Stu obtained his PhD in chemistry from UCLA in 2001 (working with Fraser Stoddart), followed by postdoctoral research at Caltech (working with Bob Grubbs). In 2003, he returned to UCLA to tackle a number of different roles, including lecturer, research associate, administrative consultant to the California NanoSystems Institute, and his first job in journal publishing — running an editorial office for the ACS journal Organic Letters. In 2006, Stu returned to the UK to join Nature Publishing Group (now Springer Nature) where he was first an associate and then senior editor at Nature Nanotechnology. In early 2008, he was appointed to be the founding Chief Editor of Nature Chemistry, which launched in April 2009. His main research interests were in the fields of supramolecular chemistry, self-assembly processes and interlocked molecules. But he’s now fascinated by scholarly communication — particularly in chemistry — and how it might be changing in the not-too-distant future. He (very occasionally) blogs about chemistry, gin and related topics at Chemical Connections (http://stuartcantrill.com) and probably tweets a bit too much.
Cyclodextrins (CD) are a well-known family of cyclic oligosaccharides obtained from the enzymatic degradation of starch1 . They possess a truncated conical structure with different cavity sizes. Their relatively hydrophobic cavity associated to the hydrophilic outer surface, enable them to form inclusion complexes in aqueous solution with a wide range of molecules of low hydrophilicity and suitable geometrical size through noncovalent host−guest interactions. Hence, CD can find applications in numerous domains like pharmaceutics, cosmetics, food, catalysis or environmental protection.
We studied extensively inclusion complexes with numerous volatile compounds (VOC, aroma, essential oils) in aqueous solutions and developed various methods to characterize these inclusion complexes2,3. We recently investigated the possibility to combine the properties of CD and deep eutectic solvents (DES)4 . DES are a new generation of green solvents reported for the first time in 20035 . The term DES is commonly used to describe low melting point liquids formed by combining organic salts and hydrogen-bond donor (HBD) components. We were able to solubilize various CD in the DES based on choline chloride:urea (1:2) and demonstrated that inclusion properties of CD were maintained in this DES4,6. To this date, few examples of inclusion complexes formation were reported in solvents other than water. Finally, low melting mixtures were obtained by mixing levulinic acid and various CD derivatives. CD also retained their inclusion ability in the resulting solvent. These new systems gave rise to a new family of solvents that we called SUPRADES7,8. In this seminar, we’ll present an overview of our main results.
1 G. Crini, S. Fourmentin, É. Fenyvesi, G. Torri, M. Fourmentin and N. Morin-Crini, Environ. Chem. Lett., 2018, 16, 1361–1375.
2 A. Ciobanu, D. Landy and S. Fourmentin, Food Res. Int., 2013, 53, 110–114.
3 M. Kfoury, L. Auezova, H. Greige-Gerges and S. Fourmentin, Anal. Chim. Acta, 2016, 918, 21–25.
4 T. Moufawad, L. Moura, M. Ferreira, H. Bricout, S. Tilloy, E. Monflier, M. C. Gomes, D. Landy and S. Fourmentin, ACS Sustain. Chem. Eng., 2019, 7, 6345–6351.
5 A. P. Abbott, G. Capper, D. L. Davies, R. K. Rasheed and V. Tambyrajah, Chem. Commun., 2003, 70–71.
6 M. E. Di Pietro, G. Colombo Dugoni, M. Ferro, A. Mannu, F. Castiglione, M. Costa Gomes, S. Fourmentin and A. Mele, ACS Sustain. Chem. Eng., 2019, 7, 17397–17405.
7 T. El Achkar, L. Moura, T. Moufawad, S. Ruellan, S. Panda, S. Longuemart, F. X. Legrand, M. Costa Gomes, D. Landy, H. Greige-Gerges and S. Fourmentin, Int. J. Pharm., 2020, 584, 119443.
8 T. El Achkar, T. Moufawad, S. Ruellan, D. Landy, H. Greige-Gerges and S. Fourmentin, Chem. Commun., 2020, 56, 3385–3388.